Effect of Inflammation on Costimulation Blockade-Resistant Allograft Rejection

Previously, we reported that allogeneic skin grafts were rapidly rejected by CD28 and CD40 ligand double deficient mice mediated by CD8⁺ T cells. These results indicated that some elements in addition to CD28- and CD40-mediated costimulation provide stimulatory signals for the activation of donor-specific CD8⁺ T cells. In this report, we investigated the role of inflammation associated with transplantation on costimulation-independent priming of CD8⁺ T cell during graft rejection. B6 RAG1 KO mice were transplanted with BALB/c-skin and adoptively transferred with syngeneic CD8⁺ T cells the same day or 50 days after transplantation. When blockade of CD28- and CD40-mediated costimulation failed to prevent acute rejection of freshly transplanted skin grafts, it efficiently delayed rejection of well-healed skin grafts. These results showed that factors associated with transplantation have essential roles in inducing costimulation blockade-resistant allograft rejection. Costimulation blockade failed to prevent acute graft-infiltration of NK cells and increasing expression of intragraft IL-12 and IL-15. These factors may trigger the graft-infiltration and priming of CD8⁺ T cells to induce costimulation blockade-resistant allograft rejection.     

Self-expandable metallic stent for unresectable malignant strictures in the esophagus and cardia

Objective Self-expandable metallic stent (EMS) placement has been the first choice for dysphagia because of the certainty over its safety, low invasiveness, and immediate efficacy. However, there still remain some problems in relation to the EMS placement site and anticancer therapies before and after EMS placement. Methods: Consecutive 78 patients in whom EMS was placed due to the unresectable malignant stricture in the esophagus or cardia from July 1995 to August 2003 in our department were studied. Results: Gastroesophageal reflux was found in 5 of 8 patients after placement of conventional EMS for the stricture in the gastroesophageal junction. Meanwhile, acid and bile reflux into the esophagus were not detected by pH and bilirubin monitoring, respectively, in 6 patients after placement of the EMS with an anti-reflux mechanism for the stricture in the gastroesophageal junction. The median survival period of all patients after EMS placement was 123 days. The median survival period of 7 patients with radiotherapy only after EMS placement was 138 days and that of 17 patients with radiotherapy before EMS placement was 60 days, which was shorter than that of the former (p<0.05). On the other hand, the median survival period after hospital admission due to dysphagia of these 7 patients was longer than that of 17 patients with radiotherapy only before EMS placement, although, the difference was not significant. Conclusion: EMS with an antireflux mechanism is not commercially available in Japan and approval is urgently required. The indication of radiotherapy associated with EMS placement is to be studied further.     

Reduction of Nitric Oxide with L–/Vc–Monomethyl Arginine in lnterleukin–2 and Anti–CD3 Monoclonal Antibody Combination Therapy

We evaluated nitric oxide induction in antitumor therapy consisting of anti–CD3 monoclonal antibody (anti–CD3) and interleukin–2 (IL–2), then determined the effect of nitric oxide reduction with L–N^G–monomethyl arginine (LNMA) on the therapeutic methods. Female C57BL/6 mice, MCA102 (a non immunogenic, NK–resistant murine fibrosarcoma cell line), and 145–2C11 (hamster anti–murine–CD3 mAb) were utilized in an experimental hepatic metastasis model developed by injecting a tumor cell suspension into the spleen of mice. A marked increase in serum NO₂^–+ NO₁ was observed at 19 hours after anti–CD3 (10 μ, IV) and additional IL–2 administrations (40times10¹ U, twice, If) induced a further increase. The NO₂, + NO_3- elevation in spot urine in the combination therapy was not suppressed with LNMA at a dose of 100 μg/h but was significantly lowered at 300 μg/h. The efficacy of the anti–CD3 + IL–2 therapy was not diminished by LNMA administration either at 100 μg/h or at 300 μg/h.     

Enhancement of bradykinin-induced prostacyclin synthesis in porcine aortic endothelial cells by pertussis toxin Possible implication of lipocortin I

Bradykinin-stimulated prostacyclin synthesis in porcine aortic endothelial cells was enhanced by pretreatment of the cells with pertussis toxin or islet-activating protein (IAP) for 5 hr or longer. Although ADP-ribosylation of a protein with a molecular weight of 41–42 kD in the cell membranes was completed by 3 hr after the addition of IAP into the incubation medium, there was good correlation between enhancement of bradykinin-induced prostacyclin synthesis and ADP-ribosylation of the IAP substrate over a wide range of IAP concentrations. Furthermore, even if IAP was removed from the incubation medium at 3 hr, bradykinin-induced prostaglandin synthesis at 24 hr was still potentiated. Cycloheximide and actinomycin D enhanced bradykinin-induced prostacyclin synthesis and apparently blocked the effect of IAP. Since this result suggested the involvement of an inhibitor protein(s) of prostacyclin synthesis in the IAP effect, we studied the effect of IAP on the level of lipocortin I which is known to inhibit phospholipase A₂. Western and Northern blot analyses revealed that IAP decreased the amounts of protein and mRNA of lipocortin I. These results suggest that the enhancement of bradykinin-induced prostacyclin synthesis by IAP is associated with a decrease in the level of lipocortin I.     

Antiphospholipid antibody syndrome and vasoocclusive diseases

One hundred and thirty-four patients with vasoocclusive diseases were retrospectively tested for three kinds of antiphospholipid antibody (aPL). The mean age at onset of the disease in 58 patients with aPL was 43 years old. Seventeen, 11, and 9 patients were positive for the aCL IgA, IgM, and IgG isotypes, respectively. The rates of anti-phospholipid syndrome (APS) in patients with arterial (n=94), venous (n= 31), or both arterial and venous (n=9) occlusion were 45%, 29%, and 78%, respectively.The rates of APS in patients with autoimmune disease (n=13), thromboangiitis obliterans (TAO) (n= 36), arteriosclerosis obliterans (ASO) with lower leg involvement (n=8) or aortic arch syndrome (n=5), Raynaud's syndrome (n=15), aortitis syndrome (n= 13), ischemic heart disease (IHD) with young onset (n =12), and bilateral leg deep venous thrombosis (DVT) (n=10) were 77%, 46%, 13%, 80%, 40%, 62%, 33%, and 70%, respectively. The cumulative patency rate for reconstructive surgery in patients (n=13) with aCL was found to be considerably lower than that in those without aCL (n=13). From these results it was concluded that IgA was the most valuable aCL isotype for the diagnosis of APS and that aPL should be examined in patients with double-vessel occlusion, autoimmune disease, bilateral leg DVT, aortic arch syndrome, TAO, Raynaud's syndrome, or IHD with young onset. Furthermore, prophylaxis for graft failure is more strongly recommended for patients with aCL than for those without it.     

Research review: DNA polymerases as molecular markers of the regenerating capacity of hepatocytes

Hepatocyte regeneration has been widely investigated, with the mitotic index and the incorporation of [³H]thymidine being used as regeneration markers. We focused on the induction of DNA replication enzymes, particularly DNA polymerases (pol) α, δ, and ε. Using rat models, we have shown that the activity of pol α in crude liver extract well represents the regenerating capacity of hepatocytes. Using pol α as an indicator, we analyzed liver regeneration in rat models under various conditions: obstructive jaundice, external or internal biliary drainage, and the obstruction of portal vein branches. It has been revealed that the ligation of the common bile duct alone induces a certain amount of hepatocyte proliferation. It was striking that external biliary drainage suppressed regeneration capacity in cholestatic rat liver after partial hepatectomy. The strong regeneration in nonligated lobes induced by portal branch ligation was similar to the liver regeneration seen after partial hepatectomy with respect to the induction of DNA polymerases. Taken together, the aspects of DNA replication, particularly the induction of DNA polymerases, may contribute to shedding new light on the regeneration of human liver. This work was supported in part by a Grant-in-Aid for General Scientific Research and for Cancer Research from the Ministry of Education, Science and Culture, Japan, and by grants from the Uehara Memorial Foundation     

The induction of operational tolerance is not prevented by simultaneous administration of cyclosporin A1

In this study, the effect of combining anti-CD4 monoclonal antibody (mAb) and cyclosporin (CyA) therapy at the time of transplantation was examined. A mouse cardiac allograft model was used. Anti-CD4 mAb administered perioperatively induces long-term survival. The addition of a short course of CyA given subcutaneously in a regimen of either a high-dose treatment or a standard dose treatment to the anti-CD4 mAb treatment protocol did not have a detrimental effect on graft survival. Despite having no significant effect on graft survival, the addition of CyA to the treatment protocol did result in a significant decrease in the level of IL-2 present in the hearts 7 days after transplantation. The decrease in IL-2 production was directly related to the presence of CyA in vivo. When CyA treatment was continued throughout the period during which unresponsiveness to the graft is induced by anti-CD4 mAb therapy, 50 % of the grafted hearts were rejected once the CyA was discontinued. In conclusion, the combined use of anti-CD4 mAb therapy and CyA did not have a negative effect on graft survival in this model when the two agents were used concurrently at the time of transplantation. Received: 2 October 1996 Received after revision: 31 January 1997 Accepted: 5 February 1997     

Successful Treatment of Adult T-cell Leukemia/Lymphoma with MACOP-B,M-FEPA and VEPP-B Combination Chemotherapy

A 45-year-old man was referred to our department in March of 1989. Physical examination showed erythroderma, palmo-plantar hyperkeratosis, generalized lymphadenopathy, hepatosplenomegaly, and leukemic manifestation. The lymphocyte count in the peripheral blood before treatment was 1.7 × 10⁴ cells/mm³. Atypical lymphocytes such as flower cells and lobulated cells were seen in the peripheral blood. A sample excised from a lymph node showed immunoblastic, pleomorphic T cells by a modified classification scheme of the Working Formulation. A high level of serum LDH was detected (2.1 times the upper normal limit). Anti HTLV-1 antibody was also detected in the serum. The atypical lymphocytes were positive for CD3, CD4, CD5, CD7 and HLA-DR, and negative for CD8. Thus, the clinical, pathologic and immunologic features were those of typical acute-type ATL. The patient was treated with VEPA-M for three months starting in March of 1989. Because of poor response, the patient was then treated with MACOP-B, M-FEPA, and VEPP-B for about one year from June of 1989 and has been free of disease up to the time of writing, March of 1993.     

AUGMENTATION OF ANGIOTENSIN II RELEASE FROM ISOLATED MESENTERIC ARTERIES OF WISTAR-KYOTO AND SPONTANEOUSLY HYPERTENSIVE RATS FOLLOWING NEPHRECTOMY

1. We previously reported that angiotensin II release from the mesenteric arteries of Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) increased in a time-dependent manner as a result of the isolation of the arteries and perfusion. This phenomenon appeared to be due to the withdrawal of circulating angiotensin II (AII). 2. The purpose of the present study was to test the hypothesis that vascular AII generation may be negatively regulated by circulating AII in WKY and SHR, and to clarify the role of this vascular angiotensin II in the sustained hypertension of SHR following nephrectomy. 3. The mesenteric arteries from kidney-intact and nephrectomized WKY and SHR were perfused and the amount of AII released into the perfusate was measured. The effects of the angiotensin converting enzyme inhibitor, captopril, and the effects of supplementation of renal renin and circulating angiotensins to nephrectomized rats, by blood exchange between kidney-intact and nephrectomized rats, on AII release were examined to clarify the pathway of vascular AII generation after nephrectomy. 4. Nephrectomy caused augmentation of vascular AII release both in WKY and SHR in spite of the abolishment of circulating renin. Captopril reduced this enhanced release of AII, but blood exchange did not affect it. There was no significant difference in these responses between WKY and SHR. 5. These results suggest that WKY and SHR have in common a potent pathway for production of vascular AII in response to the withdrawal of circulating AII, although this pathway is not responsible for the sustained hypertension of SHR after nephrectomy. The precise pathophysiological role of this pathway remains to be elucidated.     

Ontogeny of behavioral sensitization to cocaine

The ontogeny of the behavioral effects of acute cocaine administration and behavioral sensitization to cocaine in rat pups was investigated. Acute behavior stimulating effects of cocaine were observed in pups as young as 7 postnatal days (PND) old, although they needed a higher dose of cocaine than adult rats to evoke the same motor effects. An adult dose-response curve pattern of stereotypy and locomotion to acute cocaine treatment was observed at PND 21, and of rearing at PND 28. Rats aged PND 7, 14, 21, 28, and 56 received repeated injections of saline or cocaine (15 mg/kg) twice a day for 5 consecutive days. After a 3-week period of abstinence, sensitization to a challenge dose of cocaine was assessed. Cocaine-induced stereotyped behavior was enhanced significantly only in rats in which cocaine pretreatment was initiated on PND 21, 28, and 56, but not earlier on PND 7 and 14. Adult female rats given repeated cocaine injections on PND 56–60 showed significantly greater sensitization than males, but no such sex difference was observed in pups given cocaine repeatedly on PND 21–25 or 28–32. These results show clearly that cocaine-induced behavioral sensitization in rats occurred only when subchronic cocaine administration was commenced on PND 21 or later.